A wide array of investigations have focused on illustrating the effects of (in)soluble surfactants on liquid-gas confined flows, placing particular emphasis on their influence on liquid film thickness, bubble deformation, and pressure drop (see [1]} and references). The literature largely agrees that, under typical surfactant characteristics and negligible inertia, the liquid film displays a thickening response to surfactants of the order of 1 to \(4^{2/3}\)  times that predicted by [2]}'s expression for uncontaminated interfaces. This thickening has been reported to vary with \(Ca_{b}\) , surface elasticity, and across the bubble length due to Marangoni-related mechanisms, which act in opposition to liquid drag forces as they push the surfactants towards the bubble back. Nonetheless, [3]}'s numerical results in the context of pulmonary airways suggest the possibility of liquid film thinning surfactant actions under conditions of large bulk Péclet number, \(Pe_{c} >> 1\) , and \(Ca_{b} > 10^{-1}\)  due to a bifurcation and enhancement of Marangoni stresses, which drive fluid away from the thin film region and towards the bubble nose. In terms of pressure drop and bubble velocity, it has been shown that surfactants tend to increase the pressure drop across the dispersed phase [4]}, [5]} and significantly reduce the bubble's mobility along its length [6]}. [7]} carried out a comprehensive computational exploration of multiple surfactant characteristics and dimensionless groups with the novelty of introducing inertial effects (\(Re = 443 - 728\) ) to the analysis. A key finding of this work is the surfactant-induced dampening of the bubble's rear interfacial oscillatory structures, together with the evidence provided to affirm that this process is entirely Marangoni-driven rather than a consequence of localised lowered surface tension. Moreover, this investigation addressed the effect of low solubility surfactants on the bubble's dynamics, detecting a clear arrangement of the bubble's morphology into two separate regions; one fully covered in surfactants and of reduced mobility, extending from the bubble rear to a portion in the stream-wise direction that depends on \(Pe_{c}\) , and one region of diminished surfactant concentration that stretches to the bubble nose, characterised by mechanisms comparable to those of clean interfaces.
